Examine source code of Quo Vadis?

{
  "manifest_version": 2,
  "name": "Quo Vadis?",
  "description": "Reveal the chain of link redirections behind any (typically shortened) obscure URL.",
  "version": "2.0.7",
  "homepage_url": "https://basa.nl/quovadis/",
  "author": "basa",
  "developer": {
    "name": "basa",
    "url": "https://basa.nl/quovadis/"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_script.js"
      ]
    }
  ],
  "permissions": [
    "contextMenus",
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "web_accessible_resources": [
    "loading.gif",
    "icon.png"
  ],
  "icons": {
    "48": "icon.png"
  }
}